Heavy duty stapling tools are widely used in the building or construction industry, with such tools being both of the power driven type, typically pneumatic driven tools, and manual type, commonly referred to as hammer-type staplers since the tool is manually swung and impacted against a surface such as a roof or wall substrate so as to effect ejection of a staple.
To permit use of staples for securing sheathing and sheeting to walls and roofs, often as a substitute for a cap nail, tools have been developed which position a plastic cap in the discharge path of a staple so that, upon operation, the staple penetrates the cap prior to penetrating the substrate so that the cap provides significantly increased gripping strength relative to the sheathing or sheet material being fastened over the substrate. Examples of power-operated staplers which employ plastic caps are illustrated by U.S. Pat. Nos. 5,184,752, 6,302,310 and 6,478,209. In the tools of these patents, the basic stapling tool is pneumatically operated and mounts thereon a storage magazine for a plurality of plastic caps, with a leading cap being supplied into the staple discharge path for penetration by the staple during tool activation. While tools of this type perform a desirable and efficient stapling operation, nevertheless such tools may be disadvantageous with respect to their cost and their need for connection to a power source, such as a source of pressurized air for operating the tool. These tools are also generally fairly large and heavy, and the associated air hose makes tools of this type difficult to use when the sheathing or sheet material is being fastened to a relatively upright surface.
In addition, with many of the known tools, such as those illustrated in the U.S. Pat. Nos. 5,184,752 and 6,303,310 mentioned above, the tool includes a rather large upright canister for containing therein a vertical stack of caps, all of which are independent of one another, whereby loading of the tool with caps may be difficult, particularly when one considers the environment within which the tools are utilized.
Because of factors such as cost and complexity as associated with power tools as mentioned above, manually operated tools, specifically hammer-type staplers, are utilized, particularly by workmen who utilize such tool for smaller jobs or on a less frequent basis. Further, hammer-type staplers are more convenient to utilize when stapling sheathing or sheet material to a vertical or generally upright surface. In recognition of situations where hammer-type staplers are desired, it has been proposed to provide such hammer-type stapler with caps so as to increase the flexibility and improve the quality of the stapling operation being carried out. In this regard, U.S. Pat. No. 6,966,389 proposes a hammer-type cap stapler wherein a cap supply cylinder is attached to the tool for maintaining therein a vertical stack of independent caps, and the caps are discharged from the bottom of the cap cylinder so that a cap is fed into the staple discharge path for penetration by the staple during each manual activation of the tool. Further, the tool of '389 has the cap supply cylinder positioned forwardly from the impact end of the tool, which may cause overweighting of the head end of the tool and may provide an undesirable balance with respect to the feel of the tool when gripped and manually operated. The positioning of the cap storage cylinder adjacent and protruding outwardly from the impact end of the tool also prevents the tool from being utilized in close association to a wall or obstruction which protrudes upwardly from adjacent the area where stapling is desired.
Assignees co-pending U.S. Application Ser. No. 60/758,823, filed Jan. 13, 2006, now Ser. No. 11/652,333, discloses an improved manually-operated hammer-type cap stapler tool which utilizes a supply of caps defined by an elongate strip of individual caps which are serially joined edge-to-edge, with the leading cap of the strip being fed into a position aligned with the staple discharge. The cap stapler tool of this earlier application employs a wholly manually-actuated mechanism for advancing the lead cap into the discharge position, and hence provides a tool having a high degree of flexibility, mechanical simplicity and economy. Since the tool requires a deliberate manual activating of the cap feeding mechanism, however, such may be considered less effective in job situations where a large volume of impact fastening operations is to be carried out in rapid succession.
Accordingly, it is an object of this invention to provide an improved cap fastener tool, specifically a manually-operated hammer-type cap stapling tool which is manually swung and impacted against a surface to cause a stapling operation, which improved cap stapling tool is believed to provide improved constructional and operational features and to overcome many of the disadvantages discussed above.
More specifically, this invention relates to an improved manually-swingable hammer-type cap fastener tool and preferably a cap stapler tool which, in a first embodiment, utilizes a cap supply defined by an elongated row of individual caps which are serially joined edge-to-edge, with the lead cap as positioned in the fastener (i.e., staple) discharge path being separated from the serial cap strip during the fastener (i.e., staple) discharge operation, with the cap strip being automatically advanced by an inertia-activated feeding mechanism to move the next lead cap into the discharge position as a result of the preceding impact and staple discharge.
A further object of the invention is to provide an improved hammer-type cap-fastener tool, as aforesaid, wherein automatic advancing of the cap strip following each impact-discharge operation enables the tool to be easily and rapidly operated in a sequential manner without requiring any additional operation or manipulation by the operator, other than the sequential swinging and impacting of the tool against the substrate.
A still further object of the invention is to provide an improved hammer-type cap-fastener tool, as aforesaid, wherein the tool employs a feeding mechanism for advancing the lead cap into the discharge position, which feeding mechanism according to the first embodiment is activated by inertia energy associated with an activating mass which is mounted on the tool and is moveably displaced by impact of the head end of the tool against a substrate and the consequent discharge of the staple through the lead cap into the substrate, with the consequent inertia-caused movement of the mass relative to the tool being utilized to retract a cap feeding member against the urging of a spring so that the cap feeding member engages the next leading cap of the strip, with the spring thereafter advancing the feeding member and the next leading cap into the discharge position during the rebound movement of the tool away from the substrate. The advancing of the cap member by the spring also automatically resets the activating mass into its original position so as to permit inertia displacement thereof during the next succeeding impact operation. The entire movement of the cap feeding mechanism, including the inertia-caused movement of the mass and the corresponding retraction of the cap feeder, and the subsequent advancing of the cap feeder and cap and the return movement of the activating mass, all occur rapidly and sequentially during rebound of the tool immediately following the impact, thereby enabling the tool to quickly return to a reset position to permit the next impact stapling operation to be carried out. At the same time, however, the cap feeding member does not influence or detract from the manual impact force which must be applied to the tool to permit efficient carrying out of the impact stapling operation.
Still another object of the invention is to provide an improved hammer-type cap-fastener tool, as aforesaid, wherein the cap strip is formed into a spirally-wound spool which is disposed in a cap storage chamber mounted directly on the housing of the tool adjacent one side thereof, and generally between the front and rear ends of the tool, thereby minimizing the overall length of the tool. In addition, in the cap feeder mechanism of the first embodiment, the activating mass for activating the cap feeder, and the cap storage canister, are preferably disposed adjacent opposite sides of the tool to provide the tool with desirable side-to-side balance. The actuating mass is also preferably provided in close proximity to the head end of the tool so as to provide maximum efficiency with respect to generation of inertial energy, and the providing of the activating mass and the cap canister in the vicinity of the head end of the tool provides the head end with additional counter-weight effect, and hence permit the stapler tool to be constructed with lesser counter-weight mass than is typically required.
A still further object of the invention is to provide an improved hammer-type cap-fastener tool, as aforesaid, wherein the tool employs a feeding mechanism for advancing a lead cap into the discharge position, which feeding mechanism according to a second embodiment is activated by the activation of the tool during discharge of a fastener (i.e. a staple). When the head end or striker is impacted against a substrate, the striker moves relative to the tool housing to effect discharge of a staple, and this impact-induced relative movement also causes a corresponding movement of a latching member carried on the striker. This latching member, when the striker is moved into its collapsed or closed position within the housing, is spring-urged into engagement with a latch part provided on a motion transfer lever carried on the housing. The motion transfer lever in turn couples to a cap feed linkage employing a cap feed pawl which is normally spring urged into a forward or advanced position. When the latch member engages a latch part of the motion transfer lever, following the tool impact and staple discharge, the internal spring of the tool moves the striker outwardly back towards its original position which, due to the engagement between the latch member and latch part, causes the latch member to impose a force on the latch part effecting movement of the motion transfer lever, which movement is transmitted to the cap feeding mechanism and causes retraction of the cap feed pawl against the urging of its spring by a distance corresponding approximately to the width or diameter of one cap, thereby causing the cap feed pawl to engage the next succeeding cap in the cap strip. During the outward movement of the striker and the corresponding movement of the latch member, the swinging of the intermediate motion transfer member causes the latch part to disengage the latch member as the latter is moved back to its original position. As soon as the latch part is disengaged from the latch member, however, the spring acting on the cap advancing pawl immediately urges the pawl forwardly back to its original position, thereby advancing the cap strip by a distance corresponding to one cap, and also returning the motion transfer lever back to its initial position so as to be in condition to carry out the next cap advancing cycle. The entire retraction and subsequent advancing of the cap feed pawl hence occurs during the return or expansion part of a staple discharge cycle, that is, during the part of the cycle when the striker is moved outwardly back to its original position. The cap hence is automatically advanced into the discharge position during the return half of the tool cycle, with all of the movement of the cap feeding mechanism occurring during this return half of the cycle, and at the same time the impact forces imposed on the tool during the fastener discharge half of the cycle are effectively isolated from the cap feeding mechanism since the latter is engaged and activated only by the latch member on the return half cycle of the tool.
A further object of the invention is to provide an improved hammer-type cap-fastener tool, as aforesaid, wherein the serially joined caps are wound spirally into a roll or coil which can be positioned in a storage magazine mounted on the tool, thereby improving loading and storing of caps on the tool.
Another object of the invention is to provide an improved hammer-type cap-fastener tool, as aforesaid, with a cutting mechanism, similar to a scissor-type cutting structure, which effectively cuts the web or connecting strip which joins serially adjacent caps, with the cutting mechanism effecting cutting of the web so as to sever the lead cap from the remaining cap strip during the staple ejecting operation, thereby providing an improved staple/cap discharge operation which minimizes potential disturbance to the cap strip remaining in the tool.
Other objects and purposes of the improved hammer-type cap-fastener tool of the present invention will be apparent to persons familiar with stapling tools upon reading the following specification and inspecting the accompanying drawings.